Water pressure problem

[mrsbruce]

My sister needs a new bathroom, but has been told there is a problem due to water pressure. The house has an instant boiler in the kitchen, and the water tank in the loft, is only a foot or two above the ceiling height. Turning on a tap to fill a bath produces a veritable dribble of water.

Not being a plumber, and having a plumber do that teeth sucking thing, what would you venerable sages on this wonderful forum recommen.

 

[mike os]

Check pipe sizes… gravity systems need to be 22mm for main runs and baths

Also check it’s a low pressure tap

 

[dobbslc]

I have a similar set up as I'm in a chalet bungalow so the bottom of the cold tank is only 2' above the upstairs sink, we also only get a dribble from the hot tap.
I've plumbed the cold tap to mains pressure so the boys can fill up their cups at night without coming downstairs. (No dead pidgeon water )
The shower is fed from the same cold tank and hot water cylinder (the cylinder is even lower) but I've fitted a Stuart Turner negative head twin booster pump and that gives very good pressure.



I also have another Stuart Turner pump for the bathroom downstairs, although the pump wasn't needed for the bath itself SWMBO "had" to have a high pressure shower! This was the first job I had to do when we moved in!
It's a complete lash up to look at but works perfectly and will be ripped out when we re do the downstairs of the house.
You'll need a negative head or universal pump, mine is 3 bar and you can get a single if you only want to boost the hot water

 

[merryman]

I have a water tank in the loft, just above bathroom ceiling height and have no problems with water flow into the bath, big copper cylinder with immersion heater for providing the heat, next door to bathroom. I wonder if an instant boiler will have enough flow as it has, by definition, to heat the water while it is inside it.

 

[dobbslc]

Is the instant water heater feeding the bathroom? Is the bathroom upstairs like a normal house?
Just trying to get an idea what she has.

 

[JimmyS]

If its a combi boiler with a tank fed water supply then it's likely going to struggle as most combi's have a needle valve to control the max hot water flow rate as it can only heat a limited flow of water up adequately, which is on on a mains fed system but it kills the flowrate if tank fed.

You could possibly bypass the tank and pressureise the whole system but loose cold water storage. This may or may not be an issue with loss of water storage or if is some of the pipework is looking suspect and may not take pressure. Toilet float valves would likely need to be changed to high pressure ones also.

Other option is as already mentioned would be a wee booster pump and just boost the pressure in the pipework to the bath.

I'd look at just bypassing the tank personally.

 

[wristpin]

This 3bar Salamanda does the whole house, hot and cold.

 

[mrsbruce]

Is the instant water heater feeding the bathroom? Is the bathroom upstairs like a normal house?
Just trying to get an idea what she has.

Yes, but is downstairs in the kitchen.

If its a combi boiler with a tank fed water supply then it's likely going to struggle as most combi's have a needle valve to control the max hot water flow rate as it can only heat a limited flow of water up adequately, which is on on a mains fed system but it kills the flowrate if tank fed.

You could possibly bypass the tank and pressureise the whole system but loose cold water storage. This may or may not be an issue with loss of water storage or if is some of the pipework is looking suspect and may not take pressure. Toilet float valves would likely need to be changed to high pressure ones also.

Other option is as already mentioned would be a wee booster pump and just boost the pressure in the pipework to the bath.

I'd look at just bypassing the tank personally.

I wondered about a booster pump.

I’ll be back there tomorrow, and will take a look (and pictures) of/at the system. Initially, there was almost no flow out the bath hot water tap, but after a bit of ‘working’ on ‘sticky’ tap ‘things’, I got an improved flow. I will also check the water flow at the stopcock, as even in the kitchen the flow is hardly of the Niagara Falls category.

My sister will be getting rid of the bath, and fitting an electric shower unit, so she could probably live with a low flowing hot tap at the sink. I‘ll also check the settings on the boiler itself, as my late dad would fiddle with setting on everything. Considering he was 93, pretty well completely deaf and blind, and determined to live independent, I have no idea what things have been faffed with.

 

[gaz1]

either way your going to habe problems

from the read of it you have low flow from the mains as well its also not good with showers either

this means you may have to fit a tank in the loft as well as a pump and also a shower

so not as easy as you may think for a fix there

one other thing open and close the taps a few times and tap the stop tap as you need to knock any crap theyve gained whilst being used make sure you have a running tap on at start of doing it and dont flush that toilet you dont want any dirt aiming for the toilet

fill up points here take a photo of the sink and take another photo when its filled from the tap in 1 minute to fill then measure the bowl as we can get sizes on how fast they fill

 

[colnerov]

Is it hard or soft water area? Because it could be furred up pipes.

 

[Turbo]

We have a similar setup, 2 story house, cold water tank in attic, hot water cylinder in hotpress directly below it on first floor, heated by an oil fired cooker on ground floor.
We have great pressure in hot & cold taps in upstairs bathroom plus kitchen downstairs, all gravity fed from the cold water tank, no pumps anywhere!

@mrsbruce it sounds like a plumbing issue somewhere as that water system has been widely fitted for years & works well. It isn't unknown for the threads to fail on gate valves or stop cocks so when you turn the knob nothing happens. There could be one of them partially closed off with a dodgy thread.

 

[prepman]

My sister needs a new bathroom, but has been told there is a problem due to water pressure. The house has an instant boiler in the kitchen, and the water tank in the loft, is only a foot or two above the ceiling height. Turning on a tap to fill a bath produces a veritable dribble of water.

Not being a plumber, and having a plumber do that teeth sucking thing, what would you venerable sages on this wonderful forum recommen.

I made a stillage to overcome this issue at previous house to raise header-tank into the roof apex. Problem was upstair shower, lack of pressure.
Another way is to change cylinder if required, reverse the flow through it i.e. mains cold through heat transfer coil and tank used as thermal storage. Double/Triple coil tank. (solar system).
Using pumps you need a double impeller for hot/cold balance ideally. But pulling a partial vacuum on HWC could collapse it. Increasing 22mm pipes to 28mm effectively doubles through put. I used 28mm branching off in 22mm at this property. No mains water supply, but spring gives 50ft head (approx 1.4barg) and moved the tank into the higher part of building. No mean feat! I have to neutralise, filter and sterilise my supply. 3 pipe system. ..direct potable to cold drinking water taps, header to hot/cold for bath/shower/toilet/washing machines (dish & clothes).
I can run a bath whilst someone has a shower and flush toilet without issue. It's all down to pipe sizing and layout.